Effects of Enhanced UV‐B Radiation on Biochemical Traits in Postharvest Flowers of Medicinal Chrysanthemum

This article reported UV‐B radiation effects on biochemical traits in postharvest flowers of chrysanthemum. The experiment included six levels of UV‐B radiation (UV0, 0 μW cm^?2; UV50, 50 μW cm^?2; UV200, 200 μW cm^?2; UV400, 400 μW cm^?2; UV600, 600 μW cm^?2 and UV800, 800 μW cm^?2). Enhanced UV‐B radiation significantly increased hydrogen peroxide content (except for UV50), but did not evidently affect malondialdehyde content in flowers. Chlorophyll b and total chlorophyll content were significantly increased by UV600 and UV800. UV400 and UV600 significantly increased anthocyanins, carotenoids and UV‐B absorbing compounds content, and the activities of phenylalanine ammonia lyase (PAL) and cinnamic acid‐4‐hydroxylase (C4H) over the control. 4‐coumarate CoA ligase (4CL) activity was significantly decreased by enhanced UV‐B radiation (except for UV50). The relationships between UV‐B radiation intensities and the activities of secondary metabolism enzymes were best described by a second‐order polynomial. The R² values for UV‐B radiation intensities and the activities of PAL, C4H and 4CL were 0.8361, 0.5437 and 0.8025, respectively. The results indicated that enhanced UV‐B radiation could promote secondary metabolism processes in postharvest flowers, which might be beneficial for the accumulation of medically active ingredients in medicinal plants. The optimal UV‐B radiation intensities in the study were between UV400‐UV600.     

The Effects of Ambient Solar UV Radiation on Alkaloid Production by Erythroxylum novogranatense var. novogranatense†

Truxillines are alkaloids produced by Erythroxylum species and are thought to be derived from the UV‐driven dimerization of cinnamoylcocaines. This study was conducted to determine the effects of ambient UV radiation on the production of truxillines in Erythroxylum novogranatense var. novogranatense. Field plants were grown under shelters covered with plastic filters that were transparent to UV radiation, filtered UV‐B, or both filtered UV‐B and UV‐A radiation. The treatments had no significant effect on plant biomass or specific leaf weight. Absorption values in the UV‐C and UV‐A region of acidified‐methanol leaf extracts were higher for plants exposed to UV radiation compared to the no UV radiation treatment. There was a trend in decreasing levels of trans‐cinnamoylcocaine and a statistically significant decrease in levels of cis‐cinnamoylcocaine in the leaves of plants exposed to UV radiation compared to the no UV radiation treatment. Truxilline levels increased in leaves from plants exposed to UV radiation compared to the no UV radiation treatment. Most significantly, the ratio of truxillines to total cinnamoylcocaines in the leaves was affected by UV, increasing with increased UV exposure. The results support the hypothesis that UV radiation is involved in the formation of truxillines from cinnamoylcocaines.     

Role of Ozone in UV‐C Disinfection,Demonstrated by Comparison between Wild‐Type and Mutant Conidia of Aspergillus niger

This study aimed to investigate the tolerance of a melanized wild‐type strain of Aspergillus niger (CON1) and its light‐colored mutant (MUT1) to UV–C light and the concomitantly generated ozone. Treatments were segregated into four groups based on whether UV irradiation was used and the presence or absence of ozone: (?UV, ?O₃), (?UV, +O₃), (+UV, ?O₃) and (+UV, +O₃). The survival of CON1 and MUT1 conidia under +UV decreased as the exposure time increased, with CON1 showing greater resistance to UV irradiation than MUT1. Ozone induced CON1 conidium inactivation only under conditions of UV radiation exposure. While, the inactivation effect of ozone on MUT1 was always detectable regardless of the presence of UV irradiation. Furthermore, the CON1 conidial suspension showed lower UV light transmission than MUT1 when examined at the same concentration. Compared with the pigment in MUT1, the melanin in CON1 exhibited more potent radical‐scavenging activity and stronger UV absorbance. These results suggested that melanin protected A. niger against UV disinfection via UV screening and free radical scavenging. The process by which UV–C disinfection induces a continual decrease in conidial survival suggests that UV irradiation and ozone exert a synergistic fungicidal effect on A. niger prior to reaching a plateau.     

Development of a novel UV indicator and dosimeter film

A novel UV indicator is described, comprising nanocrystalline particles of titania dispersed in a film of a polymer, hydroxyl ethyl cellulose (HEC), containing: a mild reducing agent, triethanolamine (TEOA) and a redox indicator, methylene blue (MB). The UV indicator film is blue-coloured in the absence of UV light and loses colour upon exposure to UV light, attaining within a few min a steady-state degree of bleaching that can provide a measure of the irradiance of the incident light. The original blue colour of the film returns once the source of UV light is removed. The spectral characteristics of a typical UV indicator film, and its components, are discussed and the UV-absorbing action of the titania particles highlighted. From the measured %bleaching undergone by a typical UV indicator as a function of light irradiance the indicator appears fully bleached, within 7 min, by a UV irradiance of 3 mW cm(-2) or greater. The mechanism by which the UV indicator works is described. The reversible nature of the UV indicator is removed by covering a typical UV indicator with a thin, largely oxygen impermeable, polymer film, such as the regenerated cellulose found in Sellotape. The product is a UV dosimeter, the response of which is related to the intensity and duration of the incident UV light, as well as the amount of titania in the film. A typical UV dosimeter film is fully bleached by 250 mJ cm(-2) of UV light. The possible use of these novel indicators to measure UV exposure levels, irradiance and dose, is discussed.     

不同紫外光源下MnO2对TiO2光催化活性的影响

采用动力学方法研究了3种紫外光源下MnO2颗粒物对TiO2光催化活性的影响, 使用的光源包括UV365/28 W, UV302/16 W和UV254/25 W, 实验用的MnO2包括α-MnO2, β-MnO2和δ-MnO2. 实验结果表明, 当水悬浮液中有MnO2颗粒物存在时, 在UV365/28W和UV302/16W两种紫外光源下TiO2光催化剂会失活, 而在UV254/25W紫外光源下TiO2光催化剂能基本保持稳定. TiO2光催化剂的稳定性与使用的紫外光源的波长有关.     

Surface engineering of nanoparticles for highly efficient UV‐shielding composites

Overexposure to ultraviolet (UV) with high energy can not only hurt human skin but also accelerate the degradation of organic matter. Hence, the preparation of polymer‐based UV‐shielding nanocomposites has attracted substantial attention due to the low cost, easy processing and wide applications. Notably, the highly efficient UV‐shielding polymer nanocomposites are still hindered by the agglomeration of inorganic anti‐UV nanoparticles (Nps) in polymer matrix and the narrow absorption range of UV‐shielding agents. To overcome the aforementioned bottlenecks, surface engineering of anti‐UV Nps including organic modification and inorganic hybridization has been extensively employed to enhance the UV‐shielding efficiency of composites. Herein, to deliver the readers a comprehensive understanding of the surface engineering of anti‐UV Nps, we systematically summarize the recent advances in surface organic modification and inorganic hybridization related to anti‐UV Nps. The UV‐shielding mechanism and the factors affecting UV‐shielding efficiency of polymer nanocomposites are also discussed. Finally, perspectives on remaining challenges and future development of highly efficient UV‐shielding composites are outlined.     

Diffuse component of solar ultraviolet radiation in tree shade

The first set of quantitative data of diffuse erythemal UV and UV-A radiation in tree shade at a sub-tropical Southern Hemisphere latitude is presented. Over the summer, approximately 60% of the erythemal UV radiation in tree shade is due to the diffuse component. Similarly, approximately 56% of the UV-A radiation in tree shade is due to the diffuse component. In tree shade these diffuse UV percentages are relatively constant from the morning to noon to afternoon periods. In comparison, in full sun, there is a decrease in the percentage of diffuse UV from morning to noon to afternoon. The exposures to diffuse UV on a horizontal plane in tree shade between 9:00 EST and 15:00 EST are of the order of 4 MED (minimum erythemal dose) and 14 J cm(-2) for erythemal UV and UV-A, respectively. The high diffuse UV component in the shade may result in high UV exposures not only to unprotected parts of the body on a horizontal plane, but also in equally high UV irradiances to parts of the body, including the eyes and face, that are not UV protected.     

UV dose measurements of photosensitive dermatosis patients by polycrystalline GaN-based portable self-data-acquisition UV monitors

We have developed a UV monitor with polycrystalline (poly-) gallium nitride (GaN) UV sensors and evaluated its performance from the viewpoint of its effectiveness for use with photosensitive dermatosis patients. The poly-GaN UV sensor is sensitive to UV light from 280 to 410 nm even without optical filters. The UV monitor is a portable self-data-acquisition instrument with a minimum detection level (defined as average UV intensity over 290 to 400 nm) of 2 microW/cm2 and can store UV dose data for 128 days. It allows easy measurement of four orders of magnitude of ambient UV intensity and dose from indoor light to direct solar radiation in summer. Trial use of the UV monitor by five xeroderma pigmentosum patients started in June 2000 and was carried out for 1 year. It was demonstrated that the UV monitor was useful in improving their quality of life.     

Preparation of Photo-responsive DNA Supramolecular Hydrogels and Their Application as UV Radiometers

Ultraviolet light(UV) is an essential component of ambient light, but high dose UV would damage genome DNA. While semiconductors and soft materials have been employed to detect the UV, the complex process and the instrumental requirement have limited the application in daily life. In this study, taking advantage of sequence designability, a series of hydrogels with different gel-sol transition rates was constructed under the same UV intensity by introducing competing hybridization to tune the stability of the molecular network. Through estimating the transition time between each system under UV light irradiation, the intensity of UV could be roughly estimated, which provided a convenient method for the visual detection of UV.     

Comparison of two post-column derivatization systems, ultraviolet irradiation and electrochemical determination, for the liquid chromatographic determination of aflatoxins in food

This study compared 2 post-column derivatization (PCD) techniques for the determination of aflatoxins B1, B2, G1, and G2 (AFB1, AFB2, AFG1, and AFG2) by fluorescence detection after liquid chromatographic separation: ultraviolet (UV) irradiation (PCD(UV)) and electrochemical bromination (PCD(EC)). Photochemical fluorescence enhancement was obtained with 2 different commercially available systems (PCD(UV1) and PCD(UV2)). An electrochemical bromination apparatus was used for bromination. Analyses of naturally contaminated or spiked samples of corn, pistachio paste, peanut butter, fig paste, and animal feed showed that neither of the techniques resulted in derivatization-specific matrix interferences for any of the matrixes under study, even when extracts were not completely purified. The response ratios PCD(UV)/PCD(EC) for AFB1, AFB2, AFG1, and AFG2 were 0.86, 0.96, 0.70, and 0.96, respectively, for PCD(UV1) and 0.82, 0.95, 0.60, and 0.90, respectively, for PCD(UV2). The long-term use of the UV lamps (300 h for PCD(UV1) and 343 h for PCD(UV2)) in the photochemical detectors showed that these ratios remained stable throughout the time frame investigated. The relative standard deviation obtained for each of the devices during the in-house validation study ranged from 0.3 to 1.8% for PCD(UV1), from 0.8 to 1.3% for PCD(UV2), and from 0.9 to 2.0% for PCD(EC).     

几种光催化反应体系中羟基自由基表观生成率的实验研究

采用邻二氮啡-Fe(Ⅱ)(橙红色)分光光度法间接测定了Fenton、UV/Fenton、UV/草酸铁/H₂O₂、UV/TiO₂4种体系中在不同条件下·OH的表观生成率,初步探讨了体系中各影响因子的作用机制.结果分析表明:对于Fenton体系、UV/Fenton、UV/草酸铁/H₂O₂而言,其最佳反应条件为pH=4.0、m(H₂O₂)/m(Fe)=1/25、铁离子的质量浓度以25 mg/L左右为宜;TiO₂光催化体系催化产生的·OH尽管受环境pH的影响相对较小,但在同等条件下·OH的表观生成率最低;4种体系中以UV/草酸铁/H₂O₂体系中·OH表观生成率最高,而且以线性的规律递增.     

Role of the UV absorber as a matrix in matrix‐assisted laser desorption/ionization mass spectrometric analysis of a mixture of a UV absorber and a stabilizer

A mixture of a UV absorber (Tinuvin 234 or Tinuvin 329) and a UV stabilizer (Tinuvin 770) was analyzed using matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) without any matrix. Fragmentation patterns of the UV absorbers and stabilizer were also investigated. The mass spectra showed the [M+H]⁺ ions and some fragment ions. Tinuvin 234, Tinuvin 329, and Tinuvin 770 generated three (m/z 119, 370, 432), one (m/z 252), and two (m/z 124 and 140) fragment ions, repectively. These fragment ions can be used to identify the chemical structures of the UV absorbers and stabilizer. Since the UV absorber performed a role as the matrix, the ion abundance of the UV stabilizer was enhanced by mixing with the UV absorber. When organic materials extracted from polypropylene (PP) containing the UV absorber and stabilizer were directly analyzed using MALDI‐MS without any matrix, the protonated molecule of the UV stabilizer was detected in abundance but the product ions of the UV absorber were not observed. When 2,5‐dihydroxybenzoic acid was used as a matrix, the protonated molecule of the UV absorber was observed. Copyright © 2010 John Wiley & Sons, Ltd.     

Hormonal Regulation of the Repair of UV Photoproducts in Melanocytes by the Melanocortin Signaling Axis

Melanoma is the deadliest form of skin cancer because of its propensity to spread beyond the primary site of disease and because it resists many forms of treatment. Incidence of melanoma has been increasing for decades. Although ultraviolet radiation (UV) has been identified as the most important environmental causative factor for melanoma development, UV‐protective strategies have had limited efficacy in melanoma prevention. UV mutational burden correlates with melanoma development and tumor progression, underscoring the importance of UV in melanomagenesis. However, besides amount of UV exposure, melanocyte UV mutational load is influenced by the robustness of nucleotide excision repair, the genome maintenance pathway charged with removing UV photoproducts before they cause permanent mutations in the genome. In this review, we highlight the importance of the melanocortin hormonal signaling axis on regulating efficiency of nucleotide excision repair in melanocytes. By understanding the molecular mechanisms by which nucleotide excision repair can be increased, it may be possible to prevent many cases of melanoma by reducing UV mutational burden over time.     

Effect of column ozone on the variability of biologically effective UV radiation at high southern latitudes

Solar irradiance measurements from Ushuaia (Argentina) and Palmer and McMurdo Stations in Antarctica covering four seasons from mid-1993 through early 1997 have been analyzed and their variations compared with column ozone changes. UV irradiances were weighted for biological effectiveness using a published biological weighting function for dose-dependent inhibition of photosynthesis by phytoplankton from the Weddell Sea. All calculations involved integrated daily UV doses and visible exposures (weighted UV and unweighted visible irradiances, respectively). The results show that daily biologically effective total UV doses underwent large short-term variations at all three sites, with day-to-day increases up to 236% at Ushuaia, 285% at Palmer and 99% at McMurdo. Parallel changes in visible exposure indicated that the total UV changes were preponderantly due to variations in cloudiness. On a 12-month basis, daily biologically effective UV doses correlated strongly with visible exposures (R > or = 0.99). Anticorrelations of total UV with ozone, on the other hand, were poor (R > -0.11). The largest daily biologically effective UV doses, and their day-to-day increases, occurred as part of the normal variability related to cloud cover and were seldom associated with significant ozone depletion. UV dose/visible exposure ratios tended to reflect ozone depletion events somewhat more consistently than UV doses alone. With the Weddell Sea phytoplankton weighting function used in this study, antarctic ozone hole events were seldom readily discernible in the biologically effective UV record. The results suggest that, where the UV sensitivity of organisms was similar to that of the Weddell Sea phytoplankton, seasonal ozone depletion had no appreciable effect on annual primary productivity during the 1993-1997 period. Additional data on the geographical and seasonal variation of biological weighting functions are desirable for more comprehensive assessments of ozone depletion effects at high southern latitudes.     

Cellular Changes Associated with the Acclimation of the Intertidal Sea Anemone Actinia tenebrosa to Ultraviolet Radiation

To assess the relative importance of long‐ and short‐term cellular defense mechanisms in seasonally UV‐R‐acclimated Actinia tenebrosa (Anthozoa, Actiniidae), individuals were exposed to summer doses of PAR, UV‐A, UV‐B and enhanced UV‐B (20%) for a period of 4 days. Mycosporine‐like amino acids (MAAs) and cyclobutane pyrimidine dimer (CPD) concentrations were quantified, while oxidative damage to lipids and proteins, and the activities or levels of the antioxidant enzymes SOD, CAT, GR, GPOX and total glutathione were determined. Our results show that summer UV‐R‐acclimated individuals had a higher UV‐R tolerance, with no significant increases in CPDs levels, than winter‐acclimated sea anemones possibly due to higher MAA concentrations. Summer‐acclimated individuals showed increased lipid and protein oxidation and GPOX activity only when they were exposed to UV‐B at 20% above ambient UV‐R levels. In contrast, winter‐acclimated sea anemones showed elevated levels of oxidative damage, GPOX and SOD activities after exposure to UV‐A or UV‐B at ambient and elevated levels. Thus, this study indicates that long‐term UV‐R acclimation mechanisms such as the accumulation of MAAs could be more important than short‐term increases in antioxidant defenses with respect to reducing indirect UV‐R damage in intertidal sea anemones.     

UV exposure of elementary school children in five Japanese cities

A 1 week UV‐exposure measurement and outdoor‐activity pattern survey was conducted for elementary school children for four seasons at five sites in Japan, i.e. Sapporo (43°05′N, altitude 40 m), Tsukuba (36°05′N, 20 m), Tokyo (35°40′N, 45 m), Miyazaki (31°60′N, 40 m) and Naha (26°10′N, 5 m), and UV exposure was measured directly and estimated using outdoor‐activity records. The study site with largest UV exposure was Miyazaki, a southern rural area. Comparing the results for boys and girls, UV exposure was larger in boys. UV exposure was large in spring and summer and small in winter. The total amount of UV exposure in spring and summer contributed 57.7–73.4% of total exposure for the year. As a whole, 8.1% and 1.8% of the schoolchildren were exposed to more than 1 minimum erythemal dose (MED) and 2 MED of solar UV in a day, respectively. The estimated yearly UV exposure ranged from 49 207 J/m² in Miyazaki to 31 520 J/m² in Tsukuba. The actual UV exposure correlated to potential UV exposure, estimated using outdoor‐activity records and ambient UV irradiance, but the ratio differed by season and site. The yearly average of percent UV exposure to ambient UV on a horizontal plane ranged from 9.9% in Tokyo to 4.0% in Naha. In the questionnaire survey on outdoor‐activity pattern, a short question “How long did you spend time outdoors between 0900 and 1500 h?” gives the best estimates of UV exposure.     

The objective assessment of lifetime cumulative ultraviolet exposure for determining melanoma risk

Exposure to ultraviolet radiation has commonly been recognized as the most important environmental risk factor for melanoma. The measurement of UV exposure in humans, however, has proved challenging. Despite the general appreciation that an objective metric for individual UV exposure is needed to properly assess melanoma risk, little attention has been given to the issue of accuracy of UV exposure measurement. The present research utilized a GIS based historical UV exposure model (for which the accuracy of exposure estimates is known) and examined, in the case-control setting, the relative importance of UV exposure compared to self-reported time spent outdoors, in melanoma risk. UV estimates were coupled with residential histories of 820 representative melanoma cases among non-Hispanic white residents under 65 years of age from Los Angeles County and for 877 controls matched to cases by age, sex, race, and neighborhood of residence, to calculate the cumulative lifetime UV exposure and average annual UV exposure. For historical measures, when the participants resided outside the US, we also calculated UV estimates. While there was no increased risk of melanoma associated with self-reported time spent outdoors, the association between annual average UV exposure based on residential history and melanoma risk was substantial, as was the association between cumulative UV exposure based on residential history and melanoma. The time spent in outdoor activities appeared to have no significant effect on melanoma risk in any age strata, however, when adjusted for UV exposure based on residential history, time spent outdoors during young age significantly increased risk for melanoma. While there was some attenuation of risk when we excluded data from people resident overseas (as all other studies we are aware of have done), this did not significantly impact subsequent risk estimates of UV exposure on melanoma.     

Comparison of UV Protection Properties of Cotton Fabrics Treated with Aqueous and Methanolic Extracts of Achyranthes aspera and Alhagi maurorum Plants

UV radiations are high‐energy radiations present in sunlight that can damage human skin. Protection against these radiations becomes vital especially in those areas of the globe where UV index is quite high that makes the inhabitants more prone to dangerous effects of UV radiations. Clothing materials are good blockers of UV radiations, particularly when the fabric cover factor is high and/or the fabrics contain suitable UV‐blocking finishes. In this study, effect of application of aqueous and methanolic extracts of two different plants, i.e., Achyranthes aspera and Alhagi maurorum on UV protection properties of cotton fabric was investigated. The results showed that the fabric samples treated with extracts of both the plants have excellent UV protection properties as indicated by their ultraviolet protection factor. It was concluded that both the aqueous and methanolic plant extracts are very effective in blocking UVA and UVB radiations, when applied on cotton fabrics. The UV protection performance of Achyranthes aspera extracts was much better as compared to that of Alhagi maurorum, and methanolic extracts of both the plants outperformed the aqueous extracts in terms of UV protection.     

氟硅结构对UV涂料疏水疏油性的影响

UV防污助剂主要包括有机氟和有机硅等，前者结构主要是全氟聚醚链段，后者结构主要是聚二甲基硅氧烷链，利用氟硅的低表面张力起到防污作用，所以主要链段结构的细微差异会导致性能的明显变化。本文选取C1607、C1603和KY1203分别代表聚二甲基硅氧烷、K型全氟聚醚链段和Z型全氟聚醚链段，并与UV涂料复配和固化，研究不同氟硅链段对UV涂料的疏水疏油性能的影响规律。结果证明，聚二甲基硅氧烷链段具有较强的迁移性，低添加量就可达到疏水效果，但仅能应用于低端的防水防油需求。全氟聚醚类UV防污助剂的疏水疏油性能要远优于有机硅，在较高添加量时K型全氟聚醚类UV防污助剂具有更强的疏水疏油性能。     

Effects of Suplementary Ultraviolet‐B Irradiance on Maize Yield and Qualities: A Field Experiment¶

Stratospheric ozone depletion has caused an increase in the amount of ultraviolet‐B (UV‐B) radiation reaching the earth's surface. Numerous investigations have demonstrated that the effect of UV‐B enhancements on plants includes reduction in grain yield, alteration in species competition, susceptibility to disease and changes in plant structure and pigmentation. Many experiments examining UV‐B radiation effects on plants have been conducted in growth chambers or greenhouses. It has been questioned whether the effect of UV‐B radiation on plants can be extrapolated to field responses from indoor studies because of the unnaturally high ratios of UV‐B/ ultraviolet‐A radiation (320–400 nm) and UV‐B/photosynthetically active radiation (PAR) in many indoor studies. Field studies on UV‐B radiation effect on plants have been recommended to use the UV and PAR irradiance provided by natural light. This study reports the growth and yield responses of a maize crop exposed to enhanced UV‐B radiation and the UV‐B effects on aize seed qualities under field conditions. Enhanced UV‐B radiation caused a significant reduction in the dry matter accumulation and the maize yield in turn was affected. With increased UV‐B radiation the flavonoid accumulation in maize leaves increased and the contents of chlorophyll a, b and (a+b) of maize leaves were reduced. The levels of protein, sugar and starch of maize seed decreased with enhanced UV‐B radiation, whereas the level of lysine increased with enhanced UV‐B radiation.